A preparation method of sodium gold sulfite solution

Abstract

The invention relates to a method for preparing a sodium gold sulfite solution. The method comprises the following steps: S1, preparing chloroauric acid; S2, slowly dropping the prepared chloroauric acid into the sodium sulfite solution, temporarily stopping the dropping of the chloroauric acid when the solution turns light yellow, adjusting the pH value, and continuing to drop the chloroauric acid after the solution turns colorless and transparent until the chloroauric acid is completely dropped, thereby obtaining a crude sodium gold sulfite solution; S3, adding ethanol to the crude sodium gold sulfite solution, using an antisolvent to precipitate a crystal product, and washing the crystal product with ethanol for multiple times after solid-liquid separation, thereby obtaining sodium gold sulfite crystals; and S4, dissolving the obtained sodium gold sulfite crystals in the sodium sulfite solution to prepare the sodium gold sulfite solution, thereby obtaining the sodium gold sulfite solution.

Description

Technical Field

[0001] The invention relates to the field of preparation of sodium gold sulfite, and in particular to a method for preparing a sodium gold sulfite solution. Background Art

[0002] Sodium gold sulfite is the primary gold salt used in sulfite gold plating systems. Its gold-plated layer exhibits strong resistance to discoloration and can be used as a decorative coating. Furthermore, gold-plated layers made with sodium gold sulfite exhibit excellent properties such as corrosion and wear resistance, low contact resistance, and good solderability. They can also serve as functional and protective coatings, finding widespread use in printed circuit boards, semiconductor electronic component manufacturing, and cutting-edge military equipment.

[0003] In terms of the preparation of sodium gold sulfite solution, patent CN113046800A discloses a sodium gold sulfite electroplating solution and a preparation method thereof, comprising the following steps: adding gold to aqua regia and dissolving it at 90-100°C for 1-3 hours; keeping the temperature at 90-100°C for 3-5 hours, concentrating chloroauric acid into a syrup, and adding concentrated hydrochloric acid to the concentrated chloroauric acid several times to remove nitrate; placing the solution after volume adjustment in an ice-water bath, and adding saturated sodium hydroxide dropwise to the chloroauric acid solution while stirring in the ice-water bath to adjust the pH to 6-7; adding the pH-adjusted chloroauric acid solution to the sodium sulfite solution while stirring, and continuing to stir for 1-2 hours.

[0004] 1.5 hours; wait until the solution fades from yellow to colorless and transparent, then filter to obtain a sodium gold sulfite electroplating solution. This patent does not remove chloride ions, so chloride ions entrained and adsorbed by gold will still be present in the product. This patent is completely different from the electrolytic method for preparing gold hydroxide in this patent. Patent CN105568269A discloses a method for preparing sodium gold sulfite, a cyanide-free gold plating reagent, using a process that involves gold crushing, gold nugget cleaning, gold dissolution, nitrate removal, alkalization, cleaning, complexation reaction, and concentration and crystallization. By controlling the pH, an intermediate product, Au(OH)3 precipitate, is prepared, and the chloride ions in the product are removed by washing with deionized water. The Au(OH)3 precipitate is complexed with a sodium sulfite solution to prepare a sodium gold sulfite solution, which is then concentrated to obtain sodium gold sulfite crystals. This method suffers from low yield and chloride ion corrosion of the plating racks and tanks.

[0005] Furthermore, during the preparation process, the yield of sodium gold sulfite in the reaction is related to the pH value of the reaction solution. The yield is highest when the pH value is controlled at a specific value. When the pH changes, incomplete reaction of chloroauric acid will cause the reaction solution to exhibit the pale yellow color of chloroauric acid. Because chloroauric acid is a strong acid, sodium hydroxide solution needs to be continuously added during the addition of sodium sulfite solution to adjust the pH value of the reaction solution to maintain the pH value at the target value. The prior art determines the pH value of the reaction solution by observing the color change in the reaction vessel. When the reaction solution exhibits a pale yellow color after adding chloroauric acid, sodium hydroxide solution is added to return the pH to the target value and allow the chloroauric acid to fully react, returning the reaction solution to a transparent color. On the one hand, this technical approach can only be based on the operator's rough observation or operation, which is subject to human error. On the other hand, sodium hydroxide solution has a certain viscosity. During the process of outputting sodium hydroxide, sodium hydroxide is easily adsorbed at the opening of the dropper and aggregated into droplets of varying sizes before dripping, making it difficult to control the amount of sodium hydroxide added.

[0006] The purpose of the present invention is to design a method for preparing a sodium gold sulfite solution in response to the above-mentioned problems in the prior art. Summary of the Invention

[0007] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for preparing a sodium gold sulfite solution, which can effectively solve at least one problem existing in the above-mentioned prior art.

[0008] The technical solution of the present invention is:

[0009] A method for preparing a sodium gold sulfite solution comprises the following steps:

[0010] S1. preparing chloroauric acid;

[0011] S2. Slowly add the prepared chloroauric acid dropwise to the sodium sulfite solution. When the solution turns light yellow, temporarily stop adding the chloroauric acid dropwise and adjust the pH. After the solution becomes colorless and transparent, continue adding the chloroauric acid dropwise until the chloroauric acid is completely added to obtain a crude sodium gold sulfite solution.

[0012] S3, adding ethanol to the crude sodium gold sulfite solution, precipitating a crystalline product with an anti-solvent, and washing the crystalline product with ethanol multiple times after solid-liquid separation to obtain sodium gold sulfite crystals;

[0013] S4. Dissolving the obtained sodium gold sulfite crystals in a sodium sulfite solution to prepare a sodium gold sulfite solution, thereby obtaining a sodium gold sulfite solution.

[0014] Furthermore, in step S2, the pH is adjusted to 7.5-9.

[0015] Furthermore, in step S1, chloroauric acid is prepared by dissolving gold in aqua regia.

[0016] Furthermore, in step S3, after obtaining the sodium gold sulfite crystals, the solution is allowed to stand to allow the ethanol to evaporate.

[0017] Furthermore, step S2 is based on a preparation device, and the preparation device includes:

[0018] A reaction bottle is provided with a stirring element, and the reaction bottle is used to store sodium sulfite;

[0019] a first receiving bottle and a first pump body, wherein the first receiving bottle is used to store chloroauric acid, and the first pump body outputs chloroauric acid to the reaction bottle through a first pipe;

[0020] a second receiving bottle and a second pump body, wherein the second receiving bottle is used to store sodium hydroxide, and the second pump body outputs sodium sulfite to the reaction bottle through a second pipe;

[0021] A droplet size adjustment mechanism includes a spring and a driving member. The bottom end of the spring is fixedly connected to the liquid outlet end of the second pipe, and the distal end of the spring extends to the lower side of the liquid outlet end of the second pipe. After the liquid is discharged from the second pipe, the droplets are attracted to the bottom end of the spring, converge, and then drip. The driving member is connected to the top end of the spring. The driving member stretches or relaxes the spring to change the pitch of the spring. The pitch of the spring is negatively correlated with the adsorption force of the spring on the droplets.

[0022] A visual mechanism, provided on the side of the reaction bottle, for obtaining the color inside the reaction bottle;

[0023] A control system controls the amount by which the drive member stretches the spring based on the color detected by the visual mechanism, thereby controlling the particle size of the droplets output from the second pipe. Furthermore, the spring is a tower spring. Furthermore, the spring is provided with elastic rods spaced apart along its winding direction, the elastic rods being arranged obliquely upward. Furthermore, when the spring is compressed, the elastic rods elastically deform and attach to the inner coil of the spring. When the spring is stretched, the elastic rods elastically deform and swing toward the outer coil of the spring, thereby disengaging the droplets output from the second pipe.

[0024] Therefore, the present invention provides the following effects and / or advantages:

[0025] This application utilizes the characteristics of sodium gold sulfite crystals being readily soluble in water but poorly soluble in anhydrous ethanol solvent to precipitate the sodium gold sulfite crystals from the solution using an ethanol solvent. The method primarily involves steps such as gold treatment, dissolution in aqua regia, preparation of a sodium hydroxide solution, pH adjustment with chloroauric acid, preparation of an anhydrous sodium sulfite solution, complexation reaction, alcohol extraction, baking the sodium gold sulfite crystals, dissolution in water, and filtration. This preparation method effectively removes chloride ions by washing, reducing the chloride ion content of the sodium gold sulfite solution to below 30 ppm. The chloride ions are retained in the precipitated solution, and the crystals are then used to prepare the sodium gold sulfite solution, thereby achieving the purpose of separating the chloride ions. After ethanol washing, the chloride ion content of the final product is less than 30 ppm.

[0026] The process of the present application uses aqua regia to dissolve gold to obtain chloroauric acid, which is then directly reacted with anhydrous sodium sulfite for a complex reaction. The liquid-liquid reaction rate is fast, and ethanol can be used to reverse the solution to precipitate sodium gold sulfite with a precipitation rate of more than 99%. The produced sodium gold sulfite can be filtered and washed quickly, and the preparation only takes one day, which greatly reduces production time.

[0027] The process provided in this application clarifies the process reaction mechanism, optimizes process parameters, and obtains the optimal operating process.

[0028] In the present application, chloroauric acid is stored in a first holding bottle and input into a reaction bottle containing sodium sulfite for reaction to generate sodium gold sulfite. During the reaction, sodium hydroxide stored in a second holding bottle is added dropwise to the reaction bottle to adjust the pH value in the reaction bottle. A droplet size adjustment mechanism is used to adjust the particle size of the output sodium hydroxide droplets, so that sodium hydroxide droplets of corresponding particle size can be accurately output for adjusting the pH value in the reaction bottle.

[0029] The present application stretches the spring through a driving member, thereby changing the pitch of the spring, and the pitch is used to adjust the contact amount of the spring with the droplet, and to adjust the adsorption force of the spring on the droplet, thereby changing the particle size of the droplet.

[0030] The present application provides an elastic rod on the spring, which can be rebounded from the inner ring of the spring to the outer ring of the spring after the spring is stretched. This action can cause the droplets adsorbed on the bottom end of the spring to fall off, thereby obtaining droplets of smaller particle size.

[0031] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0032] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of a flow chart of an embodiment of the present invention.

[0034] Figure 2 Schematic diagram of the structure of an embodiment of the present invention.

[0035] Figure 3 Schematic diagram of the structure of the droplet size adjustment mechanism.

[0036] Figure 4 Schematic diagram of the state where droplets are adsorbed on the droplet size adjustment mechanism.

[0037] Figure 5 This is a schematic diagram of the state in which the elastic rod is placed on the inner ring of the spring.

[0038] Figure 6 It is a schematic diagram of the state in which the elastic rod is swung toward the outer ring of the spring.

[0039] Description of reference numerals:

[0040] Reaction bottle 1, stirring element 2, first receiving bottle 3, first pump body 4, first pipeline 5, second receiving bottle 6, second pump body 7, second pipeline 8, movable sleeve 801, droplet size adjustment mechanism 9, spring 901, driving element 902, elastic rod 903. DETAILED DESCRIPTION

[0041] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the embodiments and the accompanying drawings:

[0042] refer to Figure 1 , a method for preparing a sodium gold sulfite solution, comprising the following steps:

[0043] S1. preparing chloroauric acid;

[0044] S2. Slowly add the prepared chloroauric acid dropwise to the sodium sulfite solution. When the solution turns light yellow, temporarily stop adding the chloroauric acid dropwise and adjust the pH. After the solution becomes colorless and transparent, continue adding the chloroauric acid dropwise until the chloroauric acid is completely added to obtain a crude sodium gold sulfite solution.

[0045] S3, adding ethanol to the crude sodium gold sulfite solution, precipitating a crystalline product with an anti-solvent, and washing the crystalline product with ethanol multiple times after solid-liquid separation to obtain sodium gold sulfite crystals;

[0046] S4. Dissolving the obtained sodium gold sulfite crystals in a sodium sulfite solution to prepare a sodium gold sulfite solution, thereby obtaining a sodium gold sulfite solution.

[0047] Furthermore, in step S2, the pH is adjusted to 7.5-9.

[0048] Furthermore, in step S1, chloroauric acid is prepared by dissolving gold in aqua regia.

[0049] Furthermore, in step S3, after obtaining the sodium gold sulfite crystals, the solution is allowed to stand to allow the ethanol to evaporate.

[0050] Example 1

[0051] Aqua regia is used as a dissolving liquid to generate gold hydroxide by dissolving, filtering, complexing with sodium sulfite, and filtering to obtain a sodium gold sulfite solution. The specific process steps include:

[0052] (1) Prepare raw materials: prepare pure gold with a purity of more than 99.9%; sodium sulfite with a purity of more than 99.9%; sodium hydroxide with a purity of more than 99.9%.

[0053] (2) Preparation of gold foil: Pure gold is cut into thin slices to prepare gold foil.

[0054] (3) Preparation of chloroauric acid: Place gold foil in a nitric acid + hydrochloric acid solution, heat to 80 degrees, turn on the stirring paddle, set the speed to 300 rpm, and completely dissolve the gold foil. Then use a peristaltic pump to add sodium hydroxide, set the peristaltic pump speed to 250, and control the pH of the chloroauric acid solution to 4-5.

[0055] (4) Preparation of sodium sulfite solution: Dissolve sodium sulfite in water to prepare a sodium sulfite solution with a concentration of 0.32 mol / L.

[0056] (5) Preparation of sodium gold sulfite solution: The sodium sulfite solution in the reaction kettle was heated to 50°C and maintained at this temperature. The stirring blade was turned on and the speed was set to 300 rpm. chloroauric acid was added to the sodium sulfite solution to allow the chloroauric acid to completely react with the sodium sulfite to produce a crude sodium gold sulfite solution. The pH of the sodium gold sulfite solution was controlled at 8-9.

[0057] (6) Preparation of gold sodium sulfite solution crystals: Add alcohol to the gold sodium sulfite solution at a volume ratio of alcohol: gold sodium sulfite solution = 3:1, and extract the gold sodium sulfite crystals.

[0058] (7) Volatile alcohol: The sodium gold sulfite crystals extracted with alcohol are washed and filtered twice with alcohol. After filtering, they are transferred to a tray for drying.

[0059] (8) Prepare sodium gold sulfite solution: add pure water (water 4:1 gold) into the reactor, pour the dried sodium gold sulfite crystals into the reactor to dissolve, add anhydrous sodium sulfite (anhydrous sodium sulfite 1:1 gold) after dissolution, add dilute sulfuric acid to adjust the pH to 8.5-9 after dissolution, transfer to a bucket for filtration.

[0060] Example 2

[0061] Aqua regia is used as a dissolving liquid to generate gold hydroxide by dissolving, filtering, complexing with sodium sulfite, and filtering to obtain a sodium gold sulfite solution. The specific process steps include:

[0062] (1) Prepare raw materials: prepare pure gold with a purity of more than 99.9%; sodium sulfite with a purity of more than 99.9%; sodium hydroxide with a purity of more than 99.9%.

[0063] (2) Preparation of gold foil: Pure gold is cut into thin slices to prepare gold foil.

[0064] (3) Preparation of chloroauric acid: Place gold foil in a nitric acid + hydrochloric acid solution, heat to 92 degrees, turn on the stirring paddle, set the speed to 100 rpm, and completely dissolve the gold foil. Then use a peristaltic pump to add sodium hydroxide, set the peristaltic pump speed to 200, and control the pH of the chloroauric acid solution to 4-5.

[0065] (4) Preparation of sodium sulfite solution: Dissolve sodium sulfite in water to prepare a sodium sulfite solution with a concentration of 0.32 mol / L.

[0066] (5) Preparation of sodium gold sulfite solution: The sodium sulfite solution in the reaction kettle was heated to 62°C and maintained at this temperature. The stirring blade was turned on and the speed was set to 100 rpm. Chloroauric acid was added to the sodium sulfite solution to allow the chloroauric acid to completely react with the sodium sulfite to form the sodium gold sulfite solution. The pH of the sodium gold sulfite solution was controlled at 8-9.

[0067] (6) Preparation of gold sodium sulfite solution crystals: Add alcohol to the gold sodium sulfite solution at a volume ratio of alcohol: gold sodium sulfite solution = 4:1, and extract the gold sodium sulfite crystals.

[0068] (7) Volatile alcohol: The sodium gold sulfite crystals extracted with alcohol are washed and filtered twice with alcohol. After filtering, they are transferred to a tray for drying.

[0069] (8) Prepare sodium gold sulfite solution: add pure water (water 4:1 gold) into the reactor, pour the dried sodium gold sulfite crystals into the reactor to dissolve, add anhydrous sodium sulfite (anhydrous sodium sulfite 1:1 gold) after dissolution, add dilute sulfuric acid to adjust the pH to 8.5-9 after dissolution, transfer to a bucket for filtration.

[0070] Example 3

[0071] Aqua regia is used as a dissolving liquid to generate gold hydroxide by dissolving, filtering, complexing with sodium sulfite, and filtering to obtain a sodium gold sulfite solution. The specific process steps include:

[0072] (1) Prepare raw materials: prepare pure gold with a purity of more than 99.9%; sodium sulfite with a purity of more than 99.9%; sodium hydroxide with a purity of more than 99.9%.

[0073] (2) Preparation of gold foil: Pure gold is cut into thin slices to prepare gold foil.

[0074] (3) Preparation of chloroauric acid: Place gold foil in a nitric acid + hydrochloric acid solution, heat to 92 degrees, turn on the stirring paddle, set the speed to 100 rpm, and completely dissolve the gold foil. Then use a peristaltic pump to add sodium hydroxide, set the peristaltic pump speed to 200, and control the pH of the chloroauric acid solution to 4-5.

[0075] (4) Preparation of sodium sulfite solution: Dissolve sodium sulfite in water to prepare a sodium sulfite solution with a concentration of 0.32 mol / L.

[0076] (5) Preparation of sodium gold sulfite solution: The sodium sulfite solution in the reaction kettle was heated to 50°C and maintained at this temperature. The stirring blade was turned on and the speed was set to 100 rpm. chloroauric acid was added to the sodium sulfite solution to allow the chloroauric acid to completely react with the sodium sulfite to form the sodium gold sulfite solution. The pH of the sodium gold sulfite solution was controlled at 8-9.

[0077] (6) Preparation of gold sodium sulfite solution crystals: Add alcohol to the gold sodium sulfite solution at a volume ratio of alcohol: gold sodium sulfite solution = 4:1, and extract the gold sodium sulfite crystals.

[0078] (7) Volatile alcohol: The sodium gold sulfite crystals extracted with alcohol are washed and filtered twice with alcohol. After filtering, they are transferred to a tray for drying.

[0079] (8) Prepare sodium gold sulfite solution: add pure water (water 5:1 gold) into the reactor, pour the dried sodium gold sulfite crystals into the reactor to dissolve, add anhydrous sodium sulfite (anhydrous sodium sulfite 2:1 gold) after dissolution, add dilute sulfuric acid to adjust the pH to 8.5-9 after dissolution, transfer to a bucket for filtration.

[0080] The first-time yield of sodium gold sulfite in Example 1 was 88%, and the chloride ion was 80 ppm; the first-time yield of sodium gold sulfite in Example 2 was 95%, and the chloride ion was 30 ppm; the first-time yield of sodium gold sulfite in Example 3 was 92%, and the chloride ion was 50 ppm; and the first-time yield of sodium gold sulfite in the prior art solution was 96%, and the chloride ion was 20 ppm. It can be seen that the solution provided by Example 3 is the best.

[0081] Example 4

[0082] Step S2 is based on a preparation device for a sodium gold sulfite solution, comprising: Figure 2-3 ,

[0083] A reaction flask 1 is provided with a stirring element 2, and the reaction flask 1 is used to store sodium sulfite;

[0084] a first receiving bottle 3 and a first pump body 4, wherein the first receiving bottle 3 is used to store chloroauric acid, and the first pump body 4 outputs chloroauric acid to the reaction bottle through a first pipe 5;

[0085] a second receiving bottle 6 and a second pump body 7, wherein the second receiving bottle 6 is used to store sodium hydroxide, and the second pump body 7 outputs sodium hydroxide to the reaction bottle 1 through a second pipe 8;

[0086] In this embodiment, the first holding bottle 3, the first pump body 4, the second holding bottle 6 and the second pump body 7 can all be directly adopted from the prior art and will not be elaborated here. In order to improve the flow control of the pump body, the first pump body 4 and the second pump body 7 can adopt micro pumps.

[0087] The droplet size adjustment mechanism 9 includes a spring 901 and a driving member 902. The bottom end of the spring 901 is fixedly connected to the liquid outlet end of the second pipe 8. The end of the spring 901 extends to the lower side of the liquid outlet end of the second pipe 8. After the liquid is discharged from the second pipe 8, the droplets are attracted to the bottom end of the spring 901, converge, and then drip. The driving member 902 is connected to the top end of the spring 901. The driving member 902 stretches or relaxes the spring 901, thereby changing the pitch of the spring 901. The pitch of the spring 901 is negatively correlated with the adsorption force of the spring 901 on the droplets.

[0088] The droplet size adjustment mechanism 9 is one of the core improvements of this application. Because the sodium hydroxide solution is viscous, and the viscosity is related to the concentration of sodium hydroxide, the sodium hydroxide is more easily attracted and adsorbed on surrounding objects, and has the characteristic of being able to gather into droplets of different sizes according to concentration, external attraction, etc.

[0089] In this embodiment, the bottom end of the spring 901 extends to the lower side of the liquid outlet end of the second pipe 8. Therefore, after the sodium hydroxide is discharged from the second pipe 8, it will be pulled by the end of the spring 901 and adsorbed to the bottom end of the spring 901, gathering into droplets. As the second pipe 8 continues to discharge the sodium hydroxide solution, the droplets gathered at the bottom of the spring 901 become larger and larger. When the weight of the liquid exceeds the adsorption force of the sodium hydroxide solution on the bottom of the spring 901, the droplets fall off and drip into the reaction bottle 1.

[0090] Specifically, if Figure 4As shown, the top of the droplet will be attracted to the bottom of spring 901. When the amount of stretching of spring 901 increases, the pitch D of spring 901 increases. At this time, the coils of spring 901 are further apart from each other. After the droplet is pulled by the end of spring 901, the adsorption capacity of the bottom of spring 901 for the droplet decreases, and the droplet convergence capacity is also reduced accordingly, resulting in a smaller droplet size when dripping from the bottom of spring 901. Conversely, when the amount of stretching of spring 901 decreases, the pitch D of spring 901 decreases. At this time, the coils of spring 901 are closer to each other. After the droplet is pulled by the end of spring 901, the bottom of spring 901 is more likely to adsorb the droplet, and the droplet convergence capacity is also increased accordingly, resulting in a larger droplet size when dripping from the bottom of spring 901. Through this structural feature, by controlling the pitch of spring 901 when the second pump body 7 outputs the droplet, the droplet size can be controlled.

[0091] A visual mechanism (not shown) is provided on the side of the reaction bottle 1 and is used to obtain the color inside the reaction bottle 1; the visual mechanism may be a camera.

[0092] The control system controls the stretching amount of the spring 901 by the driving member 902 according to the color obtained by the visual mechanism, thereby controlling the particle size of the droplets output by the second pipe 8.

[0093] In the process that chloroauric acid is slowly added dropwise to transparent sodium sulfite solution, when the pH value of the solution in reaction flask 1 is not about 8, the yield of sodium sulfite gold decreases, and now chloroauric acid is not completely reacted, and residual chloroauric acid can make the reaction flask 1 present faint yellow (chloroauric acid itself is faint yellow, strong acid).By the color in reaction flask 1, the pH value in reaction flask 1 can be known.When the yellow in reaction flask 1 is darker, then shows that the pH value of solution in reaction flask 1 declines more, and the sodium hydroxide that needs to be added then needs more.But in prior art, the mode of directly dripping sodium hydroxide is generally adopted to regulate pH value, generally speaking, the volume of a drop of liquid is about 0.05 milliliter, then the amount of the sodium hydroxide that is added dropwise to reaction flask 1 at each time is fixed, is difficult to the pH value in accurate regulation reaction flask 1.

[0094] By controlling the particle size of the falling sodium hydroxide droplets, the pH of the liquid in reaction flask 1 is controlled. Preferably, controlling the pH of the liquid in reaction flask 1 to approximately 8 achieves the optimal yield of sodium gold sulfite. Therefore, when chloroauric acid is slowly delivered via the first pump body 4, the volume of sodium hydroxide solution required to be added can be estimated based on the color depth within reaction flask 1. The droplet size adjustment mechanism 9 then adjusts the volume of the sodium hydroxide droplets delivered via the second conduit 8, thereby quantitatively adjusting the volume of sodium hydroxide solution added and precisely regulating the pH within reaction flask 1.

[0095] Furthermore, the second pipe 8 is sleeved with a movable sleeve 801 , and the movable sleeve 801 is movably arranged up and down along the second pipe 8 , and the top end of the spring 901 is connected to the bottom surface of the movable sleeve 801 .

[0096] In this embodiment, the movable sleeve 801 can help the spring 901 to achieve better upward and downward stretching.

[0097] Furthermore, the liquid outlet end of the second pipe 8 is narrowed.

[0098] Furthermore, the spring 901 is a tower spring.

[0099] In this embodiment, the liquid outlet end of the second pipe 8 is narrowed, thereby ensuring that the slowly discharged sodium hydroxide solution falls in the shape of water drops. The bottom of the tower spring is narrowed, thereby better surrounding the liquid outlet end of the second pipe 8. The bottom diameter of the tower spring is small, which can better attract and adsorb the sodium hydroxide droplets.

[0100] Furthermore, the spring 901 is provided with elastic rods 903 at intervals along the winding direction thereof, and the elastic rods 903 are arranged obliquely upward.

[0101] Furthermore, when the spring 901 is compressed, the elastic rod 903 is elastically deformed and placed on the inner ring of the spring 901. When the spring 901 is stretched, the elastic rod 903 is elastically deformed and swung toward the outer ring of the spring 901, thereby separating the droplets output by the second pipe 8.

[0102] In this embodiment, the elastic rod 903 can increase the contact area between the spring 901 and the droplet, thereby improving the adsorption capacity of the bottom end of the spring 901 for the droplet; on the other hand, the elastic rod 903 can be a rubber material support with a certain bending elasticity. When the spring 901 is compressed, the elastic rod 903 is elastically deformed and placed on the inner ring of the spring 901. Figure 5 At this time, the elastic rod 903 and the spring 901 absorb the droplet together. When the spring 901 is further stretched, the pitch of the spring 901 increases. At this time, the elastic rod 903 is elastically deformed and swung toward the outer ring of the spring 901, as shown in FIG. Figure 6 As shown, under this structure, the droplets adsorbed on the bottom end of the spring 901 can be thrown off, so that they can be better separated.

[0103] A preparation process of a sodium gold sulfite solution is further provided, which comprises the following steps:

[0104] The chloroauric acid is slowly output to the sodium sulfite in the reaction bottle 1 through the first pump body 4;

[0105] Detecting the color of the reaction bottle 1 by the visual mechanism;

[0106] Controlling the driving member 902 to adjust the stretching amount of the spring 901 according to the color of the reaction bottle 1;

[0107] Sodium hydroxide droplets of corresponding droplet particle size are outputted through the second pump body 7 , so that the sodium hydroxide droplets fall off to the sodium sulfite in the reaction bottle 1 .

[0108] Further, detecting the color of the reaction bottle by the visual mechanism includes: detecting the yellow color of the reaction bottle by the visual mechanism and outputting a yellow depth value;

[0109] Controlling the driving member 902 to adjust the stretching amount of the spring 901 according to the color of the reaction bottle includes: controlling the driving member 902 to adjust the stretching amount of the spring 901 according to the yellow depth value, and the stretching amount is negatively correlated with the yellow depth value.

[0110] Furthermore, after the second pump body outputs the sodium hydroxide droplets of the corresponding droplet particle size, before the sodium hydroxide droplets fall onto the sodium sulfite in the reaction flask, the method includes:

[0111] The spring 901 is further stretched by the driving member 902 , so that the elastic rod 903 swings toward the outer ring of the spring 901 .

[0112] The principle of this embodiment can refer to the principle of a preparation device for sodium gold sulfite solution.

[0113] By using the equipment provided in this embodiment and combining it with the preparation method provided in Example 3, the primary yield of sodium gold sulfite is about 95% and the chloride ion concentration is lower than 30 ppm.

[0114] It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third etc. does not indicate any order. These words may be interpreted as names.

[0115] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0116] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0117] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

Claims

1. A method for preparing a sodium gold sulfite solution, characterized in that: The following steps are involved: S1. preparing chloroauric acid; S2. Slowly add the prepared chloroauric acid dropwise to the sodium sulfite solution. When the solution turns light yellow, temporarily stop adding the chloroauric acid dropwise and adjust the pH. After the solution becomes colorless and transparent, continue adding the chloroauric acid dropwise until the chloroauric acid is completely added to obtain a crude sodium gold sulfite solution. Step S2 is based on a preparation device, which includes: A reaction flask (1) is provided with a stirring element (2), and the reaction flask (1) is used to store sodium sulfite; a first receiving bottle (3) and a first pump body (4), wherein the first receiving bottle (3) is used to store chloroauric acid, and the first pump body (4) outputs chloroauric acid to the reaction bottle (1) through a first pipe (5); a second receiving bottle (6) and a second pump body (7), wherein the second receiving bottle (6) is used to store sodium hydroxide, and the second pump body (7) outputs sodium hydroxide to the reaction bottle (1) through a second pipe (8); A droplet size adjustment mechanism (9) comprises a spring (901) and a driving member (902), wherein the bottom end of the spring (901) is fixedly connected to the liquid outlet end of the second pipe (8), and the end of the spring (901) extends to the lower side of the liquid outlet end of the second pipe (8). After the liquid is discharged from the second pipe (8), the droplets are attracted to the bottom end of the spring (901), converge, and then drip. The driving member (902) is connected to the top end of the spring (901). The driving member (902) stretches or relaxes the spring (901) to change the pitch of the spring (901), and the pitch of the spring (901) is negatively correlated with the adsorption force of the spring (901) on the droplets. A visual mechanism, arranged on the side of the reaction bottle (1), for obtaining the color inside the reaction bottle (1); a control system for controlling the amount of stretching of the spring (901) by the driving member (902) according to the color obtained by the visual mechanism, thereby controlling the particle size of the droplets output by the second pipe (8); S3, adding ethanol to the crude sodium gold sulfite solution, precipitating a crystalline product with an anti-solvent, and washing the crystalline product with ethanol multiple times after solid-liquid separation to obtain sodium gold sulfite crystals; S4. Dissolving the obtained sodium gold sulfite crystals in a sodium sulfite solution to prepare a sodium gold sulfite solution, thereby obtaining a sodium gold sulfite solution.

2. The method for preparing a sodium gold sulfite solution according to claim 1, wherein: In step S2, the pH is adjusted to 7.5-9.

3. The method for preparing a sodium gold sulfite solution according to claim 1, wherein: In step S1, chloroauric acid is prepared by dissolving gold in aqua regia.

4. The method for preparing a sodium gold sulfite solution according to claim 1, wherein: In step S3, after obtaining sodium gold sulfite crystals, the mixture is allowed to stand to allow ethanol to evaporate.

5. The method for preparing a sodium gold sulfite solution according to claim 1, wherein: The spring (901) is a tower spring.

6. The method for preparing a sodium gold sulfite solution according to claim 5, wherein: The spring (901) is provided with elastic rods (903) at intervals along its winding direction, and the elastic rods (903) are arranged obliquely upward.

7. The method for preparing a sodium gold sulfite solution according to claim 6, wherein: When the spring (901) is compressed, the elastic rod (903) is elastically deformed and then placed on the inner ring of the spring (901); when the spring (901) is stretched, the elastic rod (903) is elastically deformed and then swung toward the outer ring of the spring (901), thereby separating the droplets output from the second pipe (8).

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